The logrotation script (/etc/cron.daily/upstart) in the Ubuntu Upstart package before 1.13.2-0ubuntu9, as used in Ubuntu Vivid 15.04, allows local users to execute arbitrary commands and gain privileges via a crafted file in /run/user/*/upstart/sessions/.

Ubuntu Vivid Upstart suffers from a logrotate privilege escalation vulnerability. Although just reported to Ubuntu, this minor dev-branch issue was already made public. As the launchpad/lkml/... feed-miners should not play all the games alone, and as others may want to learn how beginner errors still make it into packages of quite large distributions